1. Field of Invention
This invention relates in general to catalytic converters, and more specifically, to catalytic converters with a mid-bed sensor.
2. Background of Related Art
Catalytic converters include one or more catalytic elements or substrates housed in a metallic housing. The housing includes a first end and a second end. Each end portion may be conical-shaped. The catalytic converters are typically manufactured by cutting a metallic tubular member to a desired length. A respective support element is disposed around a respective substrate and thereafter inserted within the housing. The housing is formed to a targeted dimension for securing the substrates therein. One or more respective substrates may be utilized within a respective catalytic converter. Substrates are typically secured by some means to prevent movement of the substrate within the housing such as press forming the housing and support member against the outer surface of the substrate. Two substrates utilized in a catalytic converter closely positioned next to one another are less susceptible to movement or tilting after the substrates are secured within the housing by deforming the housing radially inward. However, in certain instances, the substrates are required to be spaced from each other and may be subject to movement or tilting even though the housing and support member has been secured against the substrate.
One example is when a sensor is utilized. Sensors are commonly coupled to the housing for sensing gas content passing through the substrates. The sensor is inserted through the wall of the housing and extends into the interior air space between the spaced apart substrates. The aperture for receiving the housing is typically disposed equidistant between the ends of the housing so that the sensor is positioned between the substrates.
Moreover, design constraints may dictate that the length of the converter is shorter than what is desired to secure the substrates therein. Under such conditions, the axial length of the both substrates may be shortened to accommodate the shorter design packaging. The substrates will have a greater tendency to move and tilt as the axial length of each respective substrate gets substantially equal to or less than diameter of each respective substrate. The securing of the housing and support member against the substrates may not prevent movement or tilting of the respective substrates under such conditions. There is often a trade-off that must be made between spacing required to accommodate the sensor therebetween and the length of the substrates that must be used to prevent tilting of the substrate. Moreover, when packaging is not a concern, additional length may be added to each substrate and the housing to prevent the tilting issues discussed earlier, but such additional material adds material cost to the substrate and housing.